Typically, polymer wastes or paint sludge containing a substantial volume of an inorganic filler component are disposed of via landfill. Disposal by land fill, however, has created an increasing problem because of lack of landfill space and the inability of polymers to rapidly degrade at the landfill site. In some states, paint sludge cannot be landfilled but rather must be incinerated at much greater expense. A known alternative to disposing of filled polymer waste and paint sludge by landfill is to pyrolyze the polymer or paint sludge to volatize the organic component and thus, separate the organic component from the inorganic component.
Pyrolysis is the thermal decomposition of organic matter at temperatures sufficient to volatize or gasify organic matter in the feed in the absence of oxygen or any oxidizing agent. By using a pyrolysis reaction, the inorganic components of the feed can be separated from the organic components and collected for re-use. The organic components are removed and disposed of in an environmentally safe manner.
Pyrolysis reaction assemblies are known in the prior art. In one such pyrolysis assembly, chunks of feed material (e.g., rubber tires) are introduced to a pyrolysis reactor through a reactor inlet having a cooling jacket thereon for preventing clogging of the inlet. The reaction chamber is free of oxygen or any oxidizing agent and is heated above the volatization point of any organic components of the feed material by a furnace assembly including a burner. An impeller shaft within the reaction chamber forces the inorganic and non-volatized residue progressively to an outlet. The volatized organic component is removed by a vapor outlet and is further processed. The processed organic gas has condensibles removed and is recycled and used to fuel the burner used to heat the reaction chamber. The inorganic residue having carbon residue thereon is cooled and collected for re-use.
A number of industries generate significant quantities of paint sludge and/or filled plastics such as car fluff, sheet molding compounds (SMC), reinforced reaction injection molding compounds (RRIM) and the reacting precursors of the aforesaid. If the inorganic filler component of such materials could be economically recycled for reuse into substantially the same material from which it emanated or for use in other applications, substantial reductions in landfill requirements and cost, as well as substantial reductions in the cost of fresh filler materials, would result.
It is an object of the present invention to provide a method and apparatus for continuously pyrolytically decomposing the organic component of such organic-inorganic mixtures as filled polymers and paint sludge and recovering the inorganic component thereof in a carbon-free state useful as filler in substantially the same type of material from whence it emanated.
It is a further object of the present invention to provide a continuous method and apparatus by which a feed of mixed organic and inorganic material can be pyrolytically decomposed into a recoverable inorganic filler material free of any carbon or organic residue and gaseous organic decomposition products which can be disposed of in an environmentally safe manner.
It is a still further object of the present invention to provide a continuous method and apparatus by which a feed of mixed organic and inorganic material can be introduced to an externally unheated entrance section of a pyrolysis reactor for pyrolysis in a downstream, externally heated pyrolysis section where gaseous decomposition products are generated and flowed toward the entrance section to preheat the feed and condense an organic constituent of the gaseous decomposition products on the feed for return to the pyrolysis section with the preheated feed for further decomposition.
It is a still further object of the present invention to provide a continuous method and apparatus by which a feed of mixed organic and inorganic material can be introduced to an entrance section of a pyrolysis reactor through a series of valves whose opening/closing are synchronized to one another and to a material feed device so as to supply successive incremental charges of the feed material to the reactor while maintaining an oxygen-free atmosphere therein.
Other objects and advantages of the present invention will be readily appreciated as the same becomes better understood by reference to the following detailed description thereof considered in connection with the accompanying drawings wherein: